Annotation of src/usr.bin/ssh/sshd.c, Revision 1.439
1.439 ! djm 1: /* $OpenBSD: sshd.c,v 1.438 2015/01/20 23:14:00 deraadt Exp $ */
1.86 markus 2: /*
1.65 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
1.126 deraadt 6: * This program is the ssh daemon. It listens for connections from clients,
7: * and performs authentication, executes use commands or shell, and forwards
1.65 deraadt 8: * information to/from the application to the user client over an encrypted
1.126 deraadt 9: * connection. This can also handle forwarding of X11, TCP/IP, and
10: * authentication agent connections.
1.98 markus 11: *
1.126 deraadt 12: * As far as I am concerned, the code I have written for this software
13: * can be used freely for any purpose. Any derived versions of this
14: * software must be clearly marked as such, and if the derived work is
15: * incompatible with the protocol description in the RFC file, it must be
16: * called by a name other than "ssh" or "Secure Shell".
17: *
18: * SSH2 implementation:
1.231 provos 19: * Privilege Separation:
1.126 deraadt 20: *
1.231 provos 21: * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
22: * Copyright (c) 2002 Niels Provos. All rights reserved.
1.126 deraadt 23: *
24: * Redistribution and use in source and binary forms, with or without
25: * modification, are permitted provided that the following conditions
26: * are met:
27: * 1. Redistributions of source code must retain the above copyright
28: * notice, this list of conditions and the following disclaimer.
29: * 2. Redistributions in binary form must reproduce the above copyright
30: * notice, this list of conditions and the following disclaimer in the
31: * documentation and/or other materials provided with the distribution.
32: *
33: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
34: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
36: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
37: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
42: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.65 deraadt 43: */
1.1 deraadt 44:
1.343 deraadt 45: #include <sys/types.h>
1.320 stevesk 46: #include <sys/ioctl.h>
1.321 stevesk 47: #include <sys/wait.h>
1.343 deraadt 48: #include <sys/tree.h>
1.323 stevesk 49: #include <sys/stat.h>
1.334 stevesk 50: #include <sys/socket.h>
1.340 stevesk 51: #include <sys/time.h>
1.357 djm 52: #include <sys/queue.h>
1.319 stevesk 53:
1.336 stevesk 54: #include <errno.h>
1.335 stevesk 55: #include <fcntl.h>
1.338 stevesk 56: #include <netdb.h>
1.319 stevesk 57: #include <paths.h>
1.333 stevesk 58: #include <pwd.h>
1.322 stevesk 59: #include <signal.h>
1.342 stevesk 60: #include <stdio.h>
1.341 stevesk 61: #include <stdlib.h>
1.339 stevesk 62: #include <string.h>
1.344 dtucker 63: #include <unistd.h>
1.438 deraadt 64: #include <limits.h>
1.1 deraadt 65:
1.426 markus 66: #ifdef WITH_OPENSSL
1.155 markus 67: #include <openssl/bn.h>
1.426 markus 68: #endif
1.155 markus 69:
1.343 deraadt 70: #include "xmalloc.h"
1.155 markus 71: #include "ssh.h"
72: #include "ssh1.h"
73: #include "ssh2.h"
1.1 deraadt 74: #include "rsa.h"
1.171 djm 75: #include "sshpty.h"
1.1 deraadt 76: #include "packet.h"
1.155 markus 77: #include "log.h"
1.343 deraadt 78: #include "buffer.h"
1.428 millert 79: #include "misc.h"
1.1 deraadt 80: #include "servconf.h"
81: #include "uidswap.h"
1.33 markus 82: #include "compat.h"
1.155 markus 83: #include "cipher.h"
1.415 markus 84: #include "digest.h"
1.343 deraadt 85: #include "key.h"
1.98 markus 86: #include "kex.h"
87: #include "myproposal.h"
1.108 markus 88: #include "authfile.h"
1.154 markus 89: #include "pathnames.h"
1.155 markus 90: #include "atomicio.h"
91: #include "canohost.h"
1.343 deraadt 92: #include "hostfile.h"
1.155 markus 93: #include "auth.h"
1.404 markus 94: #include "authfd.h"
1.294 djm 95: #include "msg.h"
1.186 markus 96: #include "dispatch.h"
1.206 stevesk 97: #include "channels.h"
1.230 provos 98: #include "session.h"
1.231 provos 99: #include "monitor_mm.h"
100: #include "monitor.h"
1.343 deraadt 101: #ifdef GSSAPI
102: #include "ssh-gss.h"
103: #endif
1.231 provos 104: #include "monitor_wrap.h"
1.367 andreas 105: #include "roaming.h"
1.385 djm 106: #include "ssh-sandbox.h"
1.332 stevesk 107: #include "version.h"
1.432 djm 108: #include "ssherr.h"
1.1 deraadt 109:
110: #ifndef O_NOCTTY
111: #define O_NOCTTY 0
112: #endif
113:
1.296 djm 114: /* Re-exec fds */
115: #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
116: #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
117: #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
118: #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
119:
1.138 markus 120: extern char *__progname;
121:
1.1 deraadt 122: /* Server configuration options. */
123: ServerOptions options;
124:
125: /* Name of the server configuration file. */
1.154 markus 126: char *config_file_name = _PATH_SERVER_CONFIG_FILE;
1.1 deraadt 127:
1.105 markus 128: /*
1.65 deraadt 129: * Debug mode flag. This can be set on the command line. If debug
130: * mode is enabled, extra debugging output will be sent to the system
131: * log, the daemon will not go to background, and will exit after processing
132: * the first connection.
133: */
1.1 deraadt 134: int debug_flag = 0;
135:
1.203 stevesk 136: /* Flag indicating that the daemon should only test the configuration and keys. */
137: int test_flag = 0;
138:
1.1 deraadt 139: /* Flag indicating that the daemon is being started from inetd. */
140: int inetd_flag = 0;
141:
1.135 markus 142: /* Flag indicating that sshd should not detach and become a daemon. */
143: int no_daemon_flag = 0;
144:
1.47 markus 145: /* debug goes to stderr unless inetd_flag is set */
146: int log_stderr = 0;
147:
1.1 deraadt 148: /* Saved arguments to main(). */
149: char **saved_argv;
150:
1.294 djm 151: /* re-exec */
152: int rexeced_flag = 0;
153: int rexec_flag = 1;
154: int rexec_argc = 0;
155: char **rexec_argv;
156:
1.66 markus 157: /*
1.75 markus 158: * The sockets that the server is listening; this is used in the SIGHUP
159: * signal handler.
1.66 markus 160: */
1.75 markus 161: #define MAX_LISTEN_SOCKS 16
162: int listen_socks[MAX_LISTEN_SOCKS];
163: int num_listen_socks = 0;
1.1 deraadt 164:
1.66 markus 165: /*
166: * the client's version string, passed by sshd2 in compat mode. if != NULL,
167: * sshd will skip the version-number exchange
168: */
1.61 markus 169: char *client_version_string = NULL;
1.96 markus 170: char *server_version_string = NULL;
1.1 deraadt 171:
1.404 markus 172: /* Daemon's agent connection */
1.432 djm 173: int auth_sock = -1;
1.404 markus 174: int have_agent = 0;
175:
1.66 markus 176: /*
177: * Any really sensitive data in the application is contained in this
178: * structure. The idea is that this structure could be locked into memory so
179: * that the pages do not get written into swap. However, there are some
180: * problems. The private key contains BIGNUMs, and we do not (in principle)
181: * have access to the internals of them, and locking just the structure is
182: * not very useful. Currently, memory locking is not implemented.
183: */
1.64 markus 184: struct {
1.174 deraadt 185: Key *server_key; /* ephemeral server key */
1.134 markus 186: Key *ssh1_host_key; /* ssh1 host key */
187: Key **host_keys; /* all private host keys */
1.404 markus 188: Key **host_pubkeys; /* all public host keys */
1.373 djm 189: Key **host_certificates; /* all public host certificates */
1.134 markus 190: int have_ssh1_key;
191: int have_ssh2_key;
1.169 markus 192: u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
1.1 deraadt 193: } sensitive_data;
194:
1.66 markus 195: /*
1.151 markus 196: * Flag indicating whether the RSA server key needs to be regenerated.
197: * Is set in the SIGALRM handler and cleared when the key is regenerated.
1.66 markus 198: */
1.212 markus 199: static volatile sig_atomic_t key_do_regen = 0;
1.1 deraadt 200:
1.199 markus 201: /* This is set to true when a signal is received. */
1.212 markus 202: static volatile sig_atomic_t received_sighup = 0;
203: static volatile sig_atomic_t received_sigterm = 0;
1.1 deraadt 204:
1.96 markus 205: /* session identifier, used by RSA-auth */
1.140 markus 206: u_char session_id[16];
1.96 markus 207:
1.108 markus 208: /* same for ssh2 */
1.140 markus 209: u_char *session_id2 = NULL;
1.269 markus 210: u_int session_id2_len = 0;
1.108 markus 211:
1.125 markus 212: /* record remote hostname or ip */
1.438 deraadt 213: u_int utmp_len = HOST_NAME_MAX+1;
1.125 markus 214:
1.211 markus 215: /* options.max_startup sized array of fd ints */
216: int *startup_pipes = NULL;
217: int startup_pipe; /* in child */
218:
1.231 provos 219: /* variables used for privilege separation */
1.337 dtucker 220: int use_privsep = -1;
1.285 dtucker 221: struct monitor *pmonitor = NULL;
1.386 djm 222: int privsep_is_preauth = 1;
1.231 provos 223:
1.278 markus 224: /* global authentication context */
225: Authctxt *the_authctxt = NULL;
226:
1.337 dtucker 227: /* sshd_config buffer */
228: Buffer cfg;
229:
1.299 dtucker 230: /* message to be displayed after login */
231: Buffer loginmsg;
232:
1.1 deraadt 233: /* Prototypes for various functions defined later in this file. */
1.200 itojun 234: void destroy_sensitive_data(void);
1.231 provos 235: void demote_sensitive_data(void);
1.87 markus 236:
1.426 markus 237: #ifdef WITH_SSH1
1.200 itojun 238: static void do_ssh1_kex(void);
1.426 markus 239: #endif
1.200 itojun 240: static void do_ssh2_kex(void);
1.129 provos 241:
1.87 markus 242: /*
1.75 markus 243: * Close all listening sockets
244: */
1.200 itojun 245: static void
1.75 markus 246: close_listen_socks(void)
247: {
248: int i;
1.250 deraadt 249:
1.75 markus 250: for (i = 0; i < num_listen_socks; i++)
251: close(listen_socks[i]);
252: num_listen_socks = -1;
253: }
254:
1.211 markus 255: static void
256: close_startup_pipes(void)
257: {
258: int i;
1.250 deraadt 259:
1.211 markus 260: if (startup_pipes)
261: for (i = 0; i < options.max_startups; i++)
262: if (startup_pipes[i] != -1)
263: close(startup_pipes[i]);
264: }
265:
1.75 markus 266: /*
1.65 deraadt 267: * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
268: * the effect is to reread the configuration file (and to regenerate
269: * the server key).
270: */
1.327 deraadt 271:
272: /*ARGSUSED*/
1.200 itojun 273: static void
1.64 markus 274: sighup_handler(int sig)
1.1 deraadt 275: {
1.210 deraadt 276: int save_errno = errno;
277:
1.64 markus 278: received_sighup = 1;
279: signal(SIGHUP, sighup_handler);
1.210 deraadt 280: errno = save_errno;
1.1 deraadt 281: }
282:
1.65 deraadt 283: /*
284: * Called from the main program after receiving SIGHUP.
285: * Restarts the server.
286: */
1.200 itojun 287: static void
1.165 itojun 288: sighup_restart(void)
1.1 deraadt 289: {
1.264 itojun 290: logit("Received SIGHUP; restarting.");
1.75 markus 291: close_listen_socks();
1.211 markus 292: close_startup_pipes();
1.349 dtucker 293: alarm(0); /* alarm timer persists across exec */
1.369 dtucker 294: signal(SIGHUP, SIG_IGN); /* will be restored after exec */
1.64 markus 295: execv(saved_argv[0], saved_argv);
1.264 itojun 296: logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
1.250 deraadt 297: strerror(errno));
1.64 markus 298: exit(1);
1.1 deraadt 299: }
300:
1.65 deraadt 301: /*
302: * Generic signal handler for terminating signals in the master daemon.
303: */
1.327 deraadt 304: /*ARGSUSED*/
1.200 itojun 305: static void
1.64 markus 306: sigterm_handler(int sig)
1.1 deraadt 307: {
1.199 markus 308: received_sigterm = sig;
1.1 deraadt 309: }
310:
1.65 deraadt 311: /*
312: * SIGCHLD handler. This is called whenever a child dies. This will then
1.199 markus 313: * reap any zombies left by exited children.
1.65 deraadt 314: */
1.327 deraadt 315: /*ARGSUSED*/
1.200 itojun 316: static void
1.64 markus 317: main_sigchld_handler(int sig)
1.1 deraadt 318: {
1.250 deraadt 319: int save_errno = errno;
1.239 markus 320: pid_t pid;
1.64 markus 321: int status;
1.60 deraadt 322:
1.239 markus 323: while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
324: (pid < 0 && errno == EINTR))
1.64 markus 325: ;
1.60 deraadt 326:
1.64 markus 327: signal(SIGCHLD, main_sigchld_handler);
328: errno = save_errno;
1.1 deraadt 329: }
330:
1.65 deraadt 331: /*
332: * Signal handler for the alarm after the login grace period has expired.
333: */
1.327 deraadt 334: /*ARGSUSED*/
1.200 itojun 335: static void
1.64 markus 336: grace_alarm_handler(int sig)
1.1 deraadt 337: {
1.285 dtucker 338: if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
339: kill(pmonitor->m_pid, SIGALRM);
1.394 djm 340:
341: /*
342: * Try to kill any processes that we have spawned, E.g. authorized
343: * keys command helpers.
344: */
345: if (getpgid(0) == getpid()) {
346: signal(SIGTERM, SIG_IGN);
1.416 djm 347: kill(0, SIGTERM);
1.394 djm 348: }
1.285 dtucker 349:
1.64 markus 350: /* Log error and exit. */
1.346 deraadt 351: sigdie("Timeout before authentication for %s", get_remote_ipaddr());
1.62 markus 352: }
353:
1.65 deraadt 354: /*
355: * Signal handler for the key regeneration alarm. Note that this
356: * alarm only occurs in the daemon waiting for connections, and it does not
357: * do anything with the private key or random state before forking.
358: * Thus there should be no concurrency control/asynchronous execution
359: * problems.
360: */
1.200 itojun 361: static void
1.174 deraadt 362: generate_ephemeral_server_key(void)
1.134 markus 363: {
1.191 markus 364: verbose("Generating %s%d bit RSA key.",
1.185 djm 365: sensitive_data.server_key ? "new " : "", options.server_key_bits);
1.134 markus 366: if (sensitive_data.server_key != NULL)
367: key_free(sensitive_data.server_key);
1.191 markus 368: sensitive_data.server_key = key_generate(KEY_RSA1,
1.185 djm 369: options.server_key_bits);
370: verbose("RSA key generation complete.");
1.169 markus 371:
1.356 djm 372: arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1.134 markus 373: }
1.147 deraadt 374:
1.327 deraadt 375: /*ARGSUSED*/
1.200 itojun 376: static void
1.64 markus 377: key_regeneration_alarm(int sig)
1.1 deraadt 378: {
1.64 markus 379: int save_errno = errno;
1.250 deraadt 380:
1.151 markus 381: signal(SIGALRM, SIG_DFL);
1.64 markus 382: errno = save_errno;
1.151 markus 383: key_do_regen = 1;
1.98 markus 384: }
385:
1.200 itojun 386: static void
1.96 markus 387: sshd_exchange_identification(int sock_in, int sock_out)
388: {
1.311 djm 389: u_int i;
390: int mismatch;
1.96 markus 391: int remote_major, remote_minor;
1.102 markus 392: int major, minor;
1.363 dtucker 393: char *s, *newline = "\n";
1.96 markus 394: char buf[256]; /* Must not be larger than remote_version. */
395: char remote_version[256]; /* Must be at least as big as buf. */
396:
1.103 markus 397: if ((options.protocol & SSH_PROTO_1) &&
398: (options.protocol & SSH_PROTO_2)) {
1.102 markus 399: major = PROTOCOL_MAJOR_1;
400: minor = 99;
401: } else if (options.protocol & SSH_PROTO_2) {
402: major = PROTOCOL_MAJOR_2;
403: minor = PROTOCOL_MINOR_2;
1.363 dtucker 404: newline = "\r\n";
1.102 markus 405: } else {
406: major = PROTOCOL_MAJOR_1;
407: minor = PROTOCOL_MINOR_1;
408: }
1.390 djm 409:
410: xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s",
411: major, minor, SSH_VERSION,
412: *options.version_addendum == '\0' ? "" : " ",
413: options.version_addendum, newline);
1.96 markus 414:
1.272 markus 415: /* Send our protocol version identification. */
1.367 andreas 416: if (roaming_atomicio(vwrite, sock_out, server_version_string,
1.272 markus 417: strlen(server_version_string))
418: != strlen(server_version_string)) {
419: logit("Could not write ident string to %s", get_remote_ipaddr());
1.278 markus 420: cleanup_exit(255);
1.272 markus 421: }
422:
423: /* Read other sides version identification. */
424: memset(buf, 0, sizeof(buf));
425: for (i = 0; i < sizeof(buf) - 1; i++) {
1.367 andreas 426: if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) {
1.272 markus 427: logit("Did not receive identification string from %s",
428: get_remote_ipaddr());
1.278 markus 429: cleanup_exit(255);
1.96 markus 430: }
1.272 markus 431: if (buf[i] == '\r') {
432: buf[i] = 0;
433: /* Kludge for F-Secure Macintosh < 1.0.2 */
434: if (i == 12 &&
435: strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
1.96 markus 436: break;
1.272 markus 437: continue;
438: }
439: if (buf[i] == '\n') {
440: buf[i] = 0;
441: break;
1.96 markus 442: }
443: }
1.272 markus 444: buf[sizeof(buf) - 1] = 0;
445: client_version_string = xstrdup(buf);
1.96 markus 446:
447: /*
448: * Check that the versions match. In future this might accept
449: * several versions and set appropriate flags to handle them.
450: */
451: if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
452: &remote_major, &remote_minor, remote_version) != 3) {
1.105 markus 453: s = "Protocol mismatch.\n";
1.271 deraadt 454: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.408 djm 455: logit("Bad protocol version identification '%.100s' "
456: "from %s port %d", client_version_string,
457: get_remote_ipaddr(), get_remote_port());
1.411 djm 458: close(sock_in);
459: close(sock_out);
1.278 markus 460: cleanup_exit(255);
1.96 markus 461: }
462: debug("Client protocol version %d.%d; client software version %.100s",
1.217 deraadt 463: remote_major, remote_minor, remote_version);
1.96 markus 464:
1.436 markus 465: active_state->compat = compat_datafellows(remote_version);
1.260 mickey 466:
1.413 djm 467: if ((datafellows & SSH_BUG_PROBE) != 0) {
1.264 itojun 468: logit("probed from %s with %s. Don't panic.",
1.260 mickey 469: get_remote_ipaddr(), client_version_string);
1.278 markus 470: cleanup_exit(255);
1.260 mickey 471: }
1.413 djm 472: if ((datafellows & SSH_BUG_SCANNER) != 0) {
1.264 itojun 473: logit("scanned from %s with %s. Don't panic.",
1.175 deraadt 474: get_remote_ipaddr(), client_version_string);
1.278 markus 475: cleanup_exit(255);
1.175 deraadt 476: }
1.414 djm 477: if ((datafellows & SSH_BUG_RSASIGMD5) != 0) {
1.413 djm 478: logit("Client version \"%.100s\" uses unsafe RSA signature "
479: "scheme; disabling use of RSA keys", remote_version);
1.414 djm 480: }
481: if ((datafellows & SSH_BUG_DERIVEKEY) != 0) {
482: fatal("Client version \"%.100s\" uses unsafe key agreement; "
483: "refusing connection", remote_version);
484: }
1.98 markus 485:
1.102 markus 486: mismatch = 0;
1.214 deraadt 487: switch (remote_major) {
1.96 markus 488: case 1:
1.108 markus 489: if (remote_minor == 99) {
490: if (options.protocol & SSH_PROTO_2)
491: enable_compat20();
492: else
493: mismatch = 1;
494: break;
495: }
1.102 markus 496: if (!(options.protocol & SSH_PROTO_1)) {
497: mismatch = 1;
498: break;
499: }
1.96 markus 500: if (remote_minor < 3) {
1.121 provos 501: packet_disconnect("Your ssh version is too old and "
1.96 markus 502: "is no longer supported. Please install a newer version.");
503: } else if (remote_minor == 3) {
504: /* note that this disables agent-forwarding */
505: enable_compat13();
506: }
1.102 markus 507: break;
1.98 markus 508: case 2:
1.102 markus 509: if (options.protocol & SSH_PROTO_2) {
1.98 markus 510: enable_compat20();
511: break;
512: }
1.99 markus 513: /* FALLTHROUGH */
1.105 markus 514: default:
1.102 markus 515: mismatch = 1;
516: break;
517: }
518: chop(server_version_string);
519: debug("Local version string %.200s", server_version_string);
520:
521: if (mismatch) {
1.96 markus 522: s = "Protocol major versions differ.\n";
1.271 deraadt 523: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.96 markus 524: close(sock_in);
525: close(sock_out);
1.264 itojun 526: logit("Protocol major versions differ for %s: %.200s vs. %.200s",
1.102 markus 527: get_remote_ipaddr(),
528: server_version_string, client_version_string);
1.278 markus 529: cleanup_exit(255);
1.96 markus 530: }
1.108 markus 531: }
532:
1.134 markus 533: /* Destroy the host and server keys. They will no longer be needed. */
1.108 markus 534: void
535: destroy_sensitive_data(void)
536: {
1.134 markus 537: int i;
538:
539: if (sensitive_data.server_key) {
540: key_free(sensitive_data.server_key);
541: sensitive_data.server_key = NULL;
542: }
1.217 deraadt 543: for (i = 0; i < options.num_host_key_files; i++) {
1.134 markus 544: if (sensitive_data.host_keys[i]) {
545: key_free(sensitive_data.host_keys[i]);
546: sensitive_data.host_keys[i] = NULL;
547: }
1.373 djm 548: if (sensitive_data.host_certificates[i]) {
549: key_free(sensitive_data.host_certificates[i]);
550: sensitive_data.host_certificates[i] = NULL;
551: }
1.134 markus 552: }
553: sensitive_data.ssh1_host_key = NULL;
1.418 djm 554: explicit_bzero(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1.134 markus 555: }
556:
1.231 provos 557: /* Demote private to public keys for network child */
558: void
559: demote_sensitive_data(void)
560: {
561: Key *tmp;
562: int i;
563:
564: if (sensitive_data.server_key) {
565: tmp = key_demote(sensitive_data.server_key);
566: key_free(sensitive_data.server_key);
567: sensitive_data.server_key = tmp;
568: }
569:
570: for (i = 0; i < options.num_host_key_files; i++) {
571: if (sensitive_data.host_keys[i]) {
572: tmp = key_demote(sensitive_data.host_keys[i]);
573: key_free(sensitive_data.host_keys[i]);
574: sensitive_data.host_keys[i] = tmp;
575: if (tmp->type == KEY_RSA1)
576: sensitive_data.ssh1_host_key = tmp;
577: }
1.373 djm 578: /* Certs do not need demotion */
1.231 provos 579: }
580:
581: /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
582: }
583:
1.233 markus 584: static void
1.231 provos 585: privsep_preauth_child(void)
586: {
1.253 deraadt 587: gid_t gidset[1];
1.250 deraadt 588: struct passwd *pw;
1.231 provos 589:
590: /* Enable challenge-response authentication for privilege separation */
591: privsep_challenge_enable();
1.419 djm 592:
1.420 markus 593: #ifdef GSSAPI
1.419 djm 594: /* Cache supported mechanism OIDs for later use */
595: if (options.gss_authentication)
596: ssh_gssapi_prepare_supported_oids();
1.420 markus 597: #endif
1.231 provos 598:
599: /* Demote the private keys to public keys. */
600: demote_sensitive_data();
601:
1.235 stevesk 602: if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1.240 djm 603: fatal("Privilege separation user %s does not exist",
604: SSH_PRIVSEP_USER);
1.418 djm 605: explicit_bzero(pw->pw_passwd, strlen(pw->pw_passwd));
1.235 stevesk 606: endpwent();
607:
1.255 deraadt 608: /* Change our root directory */
1.232 stevesk 609: if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
610: fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
611: strerror(errno));
1.231 provos 612: if (chdir("/") == -1)
1.236 stevesk 613: fatal("chdir(\"/\"): %s", strerror(errno));
1.234 markus 614:
1.231 provos 615: /* Drop our privileges */
1.235 stevesk 616: debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
617: (u_int)pw->pw_gid);
1.251 markus 618: #if 0
1.287 djm 619: /* XXX not ready, too heavy after chroot */
1.235 stevesk 620: do_setusercontext(pw);
1.251 markus 621: #else
622: gidset[0] = pw->pw_gid;
623: if (setgroups(1, gidset) < 0)
624: fatal("setgroups: %.100s", strerror(errno));
625: permanently_set_uid(pw);
626: #endif
1.231 provos 627: }
628:
1.278 markus 629: static int
630: privsep_preauth(Authctxt *authctxt)
1.237 markus 631: {
1.432 djm 632: int status, r;
1.237 markus 633: pid_t pid;
1.384 djm 634: struct ssh_sandbox *box = NULL;
1.237 markus 635:
636: /* Set up unprivileged child process to deal with network data */
1.242 mouring 637: pmonitor = monitor_init();
1.237 markus 638: /* Store a pointer to the kex for later rekeying */
1.434 markus 639: pmonitor->m_pkex = &active_state->kex;
1.237 markus 640:
1.393 djm 641: if (use_privsep == PRIVSEP_ON)
1.384 djm 642: box = ssh_sandbox_init();
1.237 markus 643: pid = fork();
644: if (pid == -1) {
645: fatal("fork of unprivileged child failed");
646: } else if (pid != 0) {
1.245 mpech 647: debug2("Network child is on pid %ld", (long)pid);
1.237 markus 648:
1.392 markus 649: pmonitor->m_pid = pid;
1.432 djm 650: if (have_agent) {
651: r = ssh_get_authentication_socket(&auth_sock);
652: if (r != 0) {
653: error("Could not get agent socket: %s",
654: ssh_err(r));
655: have_agent = 0;
656: }
657: }
1.384 djm 658: if (box != NULL)
659: ssh_sandbox_parent_preauth(box, pid);
1.278 markus 660: monitor_child_preauth(authctxt, pmonitor);
1.237 markus 661:
662: /* Sync memory */
1.242 mouring 663: monitor_sync(pmonitor);
1.237 markus 664:
665: /* Wait for the child's exit status */
1.384 djm 666: while (waitpid(pid, &status, 0) < 0) {
1.386 djm 667: if (errno == EINTR)
668: continue;
669: pmonitor->m_pid = -1;
670: fatal("%s: waitpid: %s", __func__, strerror(errno));
1.384 djm 671: }
1.386 djm 672: privsep_is_preauth = 0;
673: pmonitor->m_pid = -1;
1.384 djm 674: if (WIFEXITED(status)) {
675: if (WEXITSTATUS(status) != 0)
676: fatal("%s: preauth child exited with status %d",
677: __func__, WEXITSTATUS(status));
678: } else if (WIFSIGNALED(status))
679: fatal("%s: preauth child terminated by signal %d",
680: __func__, WTERMSIG(status));
681: if (box != NULL)
682: ssh_sandbox_parent_finish(box);
683: return 1;
1.237 markus 684: } else {
685: /* child */
1.383 djm 686: close(pmonitor->m_sendfd);
687: close(pmonitor->m_log_recvfd);
1.237 markus 688:
1.383 djm 689: /* Arrange for logging to be sent to the monitor */
690: set_log_handler(mm_log_handler, pmonitor);
1.237 markus 691:
692: /* Demote the child */
693: if (getuid() == 0 || geteuid() == 0)
694: privsep_preauth_child();
1.238 stevesk 695: setproctitle("%s", "[net]");
1.384 djm 696: if (box != NULL)
697: ssh_sandbox_child(box);
698:
699: return 0;
1.237 markus 700: }
701: }
702:
1.233 markus 703: static void
1.237 markus 704: privsep_postauth(Authctxt *authctxt)
1.231 provos 705: {
706: if (authctxt->pw->pw_uid == 0 || options.use_login) {
707: /* File descriptor passing is broken or root login */
708: use_privsep = 0;
1.315 djm 709: goto skip;
1.231 provos 710: }
1.234 markus 711:
1.231 provos 712: /* New socket pair */
1.242 mouring 713: monitor_reinit(pmonitor);
1.231 provos 714:
1.242 mouring 715: pmonitor->m_pid = fork();
716: if (pmonitor->m_pid == -1)
1.231 provos 717: fatal("fork of unprivileged child failed");
1.242 mouring 718: else if (pmonitor->m_pid != 0) {
1.364 markus 719: verbose("User child is on pid %ld", (long)pmonitor->m_pid);
1.307 otto 720: buffer_clear(&loginmsg);
1.242 mouring 721: monitor_child_postauth(pmonitor);
1.231 provos 722:
723: /* NEVERREACHED */
724: exit(0);
725: }
726:
1.383 djm 727: /* child */
728:
1.242 mouring 729: close(pmonitor->m_sendfd);
1.383 djm 730: pmonitor->m_sendfd = -1;
1.231 provos 731:
732: /* Demote the private keys to public keys. */
733: demote_sensitive_data();
1.354 djm 734:
1.231 provos 735: /* Drop privileges */
736: do_setusercontext(authctxt->pw);
737:
1.315 djm 738: skip:
1.231 provos 739: /* It is safe now to apply the key state */
1.242 mouring 740: monitor_apply_keystate(pmonitor);
1.312 markus 741:
742: /*
743: * Tell the packet layer that authentication was successful, since
744: * this information is not part of the key state.
745: */
746: packet_set_authenticated();
1.231 provos 747: }
748:
1.200 itojun 749: static char *
1.134 markus 750: list_hostkey_types(void)
751: {
1.223 markus 752: Buffer b;
1.281 jakob 753: const char *p;
754: char *ret;
1.134 markus 755: int i;
1.373 djm 756: Key *key;
1.223 markus 757:
758: buffer_init(&b);
1.217 deraadt 759: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 760: key = sensitive_data.host_keys[i];
1.134 markus 761: if (key == NULL)
1.404 markus 762: key = sensitive_data.host_pubkeys[i];
763: if (key == NULL)
1.134 markus 764: continue;
1.214 deraadt 765: switch (key->type) {
1.134 markus 766: case KEY_RSA:
767: case KEY_DSA:
1.378 djm 768: case KEY_ECDSA:
1.412 markus 769: case KEY_ED25519:
1.223 markus 770: if (buffer_len(&b) > 0)
771: buffer_append(&b, ",", 1);
772: p = key_ssh_name(key);
773: buffer_append(&b, p, strlen(p));
1.134 markus 774: break;
775: }
1.373 djm 776: /* If the private key has a cert peer, then list that too */
777: key = sensitive_data.host_certificates[i];
778: if (key == NULL)
779: continue;
780: switch (key->type) {
1.375 djm 781: case KEY_RSA_CERT_V00:
782: case KEY_DSA_CERT_V00:
1.373 djm 783: case KEY_RSA_CERT:
784: case KEY_DSA_CERT:
1.378 djm 785: case KEY_ECDSA_CERT:
1.412 markus 786: case KEY_ED25519_CERT:
1.373 djm 787: if (buffer_len(&b) > 0)
788: buffer_append(&b, ",", 1);
789: p = key_ssh_name(key);
790: buffer_append(&b, p, strlen(p));
791: break;
792: }
1.134 markus 793: }
1.223 markus 794: buffer_append(&b, "\0", 1);
1.281 jakob 795: ret = xstrdup(buffer_ptr(&b));
1.223 markus 796: buffer_free(&b);
1.281 jakob 797: debug("list_hostkey_types: %s", ret);
798: return ret;
1.134 markus 799: }
800:
1.373 djm 801: static Key *
1.435 markus 802: get_hostkey_by_type(int type, int need_private, struct ssh *ssh)
1.134 markus 803: {
804: int i;
1.373 djm 805: Key *key;
1.250 deraadt 806:
1.217 deraadt 807: for (i = 0; i < options.num_host_key_files; i++) {
1.375 djm 808: switch (type) {
809: case KEY_RSA_CERT_V00:
810: case KEY_DSA_CERT_V00:
811: case KEY_RSA_CERT:
812: case KEY_DSA_CERT:
1.378 djm 813: case KEY_ECDSA_CERT:
1.412 markus 814: case KEY_ED25519_CERT:
1.373 djm 815: key = sensitive_data.host_certificates[i];
1.375 djm 816: break;
817: default:
1.373 djm 818: key = sensitive_data.host_keys[i];
1.404 markus 819: if (key == NULL && !need_private)
820: key = sensitive_data.host_pubkeys[i];
1.375 djm 821: break;
822: }
1.134 markus 823: if (key != NULL && key->type == type)
1.373 djm 824: return need_private ?
825: sensitive_data.host_keys[i] : key;
1.134 markus 826: }
827: return NULL;
1.96 markus 828: }
829:
1.231 provos 830: Key *
1.435 markus 831: get_hostkey_public_by_type(int type, struct ssh *ssh)
1.373 djm 832: {
1.435 markus 833: return get_hostkey_by_type(type, 0, ssh);
1.373 djm 834: }
835:
836: Key *
1.435 markus 837: get_hostkey_private_by_type(int type, struct ssh *ssh)
1.373 djm 838: {
1.435 markus 839: return get_hostkey_by_type(type, 1, ssh);
1.373 djm 840: }
841:
842: Key *
1.231 provos 843: get_hostkey_by_index(int ind)
844: {
845: if (ind < 0 || ind >= options.num_host_key_files)
846: return (NULL);
847: return (sensitive_data.host_keys[ind]);
848: }
849:
1.404 markus 850: Key *
1.435 markus 851: get_hostkey_public_by_index(int ind, struct ssh *ssh)
1.404 markus 852: {
853: if (ind < 0 || ind >= options.num_host_key_files)
854: return (NULL);
855: return (sensitive_data.host_pubkeys[ind]);
856: }
857:
1.231 provos 858: int
1.435 markus 859: get_hostkey_index(Key *key, struct ssh *ssh)
1.231 provos 860: {
861: int i;
1.250 deraadt 862:
1.231 provos 863: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 864: if (key_is_cert(key)) {
865: if (key == sensitive_data.host_certificates[i])
866: return (i);
867: } else {
868: if (key == sensitive_data.host_keys[i])
869: return (i);
1.404 markus 870: if (key == sensitive_data.host_pubkeys[i])
871: return (i);
1.373 djm 872: }
1.231 provos 873: }
874: return (-1);
875: }
876:
1.439 ! djm 877: /* Inform the client of all hostkeys */
! 878: static void
! 879: notify_hostkeys(struct ssh *ssh)
! 880: {
! 881: struct sshbuf *buf;
! 882: struct sshkey *key;
! 883: int i, nkeys, r;
! 884: char *fp;
! 885:
! 886: if ((buf = sshbuf_new()) == NULL)
! 887: fatal("%s: sshbuf_new", __func__);
! 888: for (i = nkeys = 0; i < options.num_host_key_files; i++) {
! 889: key = get_hostkey_public_by_index(i, ssh);
! 890: if (key == NULL || key->type == KEY_UNSPEC ||
! 891: key->type == KEY_RSA1 || sshkey_is_cert(key))
! 892: continue;
! 893: fp = sshkey_fingerprint(key, options.fingerprint_hash,
! 894: SSH_FP_DEFAULT);
! 895: debug3("%s: key %d: %s %s", __func__, i,
! 896: sshkey_ssh_name(key), fp);
! 897: free(fp);
! 898: if ((r = sshkey_puts(key, buf)) != 0)
! 899: fatal("%s: couldn't put hostkey %d: %s",
! 900: __func__, i, ssh_err(r));
! 901: nkeys++;
! 902: }
! 903: if (nkeys == 0)
! 904: fatal("%s: no hostkeys", __func__);
! 905: debug3("%s: send %d hostkeys", __func__, nkeys);
! 906: packet_start(SSH2_MSG_GLOBAL_REQUEST);
! 907: packet_put_cstring("hostkeys@openssh.com");
! 908: packet_put_char(0); /* want-reply */
! 909: packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
! 910: packet_send();
! 911: }
! 912:
1.124 markus 913: /*
914: * returns 1 if connection should be dropped, 0 otherwise.
915: * dropping starts at connection #max_startups_begin with a probability
916: * of (max_startups_rate/100). the probability increases linearly until
917: * all connections are dropped for startups > max_startups
918: */
1.200 itojun 919: static int
1.124 markus 920: drop_connection(int startups)
921: {
1.303 mickey 922: int p, r;
1.124 markus 923:
924: if (startups < options.max_startups_begin)
925: return 0;
926: if (startups >= options.max_startups)
927: return 1;
928: if (options.max_startups_rate == 100)
929: return 1;
930:
931: p = 100 - options.max_startups_rate;
932: p *= startups - options.max_startups_begin;
1.303 mickey 933: p /= options.max_startups - options.max_startups_begin;
1.124 markus 934: p += options.max_startups_rate;
1.356 djm 935: r = arc4random_uniform(100);
1.124 markus 936:
1.304 djm 937: debug("drop_connection: p %d, r %d", p, r);
1.124 markus 938: return (r < p) ? 1 : 0;
939: }
940:
1.215 markus 941: static void
942: usage(void)
943: {
1.290 markus 944: fprintf(stderr, "%s, %s\n",
1.426 markus 945: SSH_VERSION,
946: #ifdef WITH_OPENSSL
947: SSLeay_version(SSLEAY_VERSION)
948: #else
949: "without OpenSSL"
950: #endif
951: );
1.289 markus 952: fprintf(stderr,
1.373 djm 953: "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n"
1.399 dtucker 954: " [-E log_file] [-f config_file] [-g login_grace_time]\n"
955: " [-h host_key_file] [-k key_gen_time] [-o option] [-p port]\n"
956: " [-u len]\n"
1.289 markus 957: );
1.215 markus 958: exit(1);
959: }
960:
1.294 djm 961: static void
962: send_rexec_state(int fd, Buffer *conf)
963: {
964: Buffer m;
965:
966: debug3("%s: entering fd = %d config len %d", __func__, fd,
967: buffer_len(conf));
968:
969: /*
970: * Protocol from reexec master to child:
971: * string configuration
972: * u_int ephemeral_key_follows
973: * bignum e (only if ephemeral_key_follows == 1)
974: * bignum n "
975: * bignum d "
976: * bignum iqmp "
977: * bignum p "
978: * bignum q "
979: */
980: buffer_init(&m);
981: buffer_put_cstring(&m, buffer_ptr(conf));
982:
1.426 markus 983: #ifdef WITH_SSH1
1.298 deraadt 984: if (sensitive_data.server_key != NULL &&
1.294 djm 985: sensitive_data.server_key->type == KEY_RSA1) {
986: buffer_put_int(&m, 1);
987: buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
988: buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
989: buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
990: buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
991: buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
992: buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
993: } else
1.426 markus 994: #endif
1.294 djm 995: buffer_put_int(&m, 0);
996:
997: if (ssh_msg_send(fd, 0, &m) == -1)
998: fatal("%s: ssh_msg_send failed", __func__);
999:
1000: buffer_free(&m);
1001:
1002: debug3("%s: done", __func__);
1003: }
1004:
1005: static void
1006: recv_rexec_state(int fd, Buffer *conf)
1007: {
1008: Buffer m;
1009: char *cp;
1010: u_int len;
1011:
1012: debug3("%s: entering fd = %d", __func__, fd);
1013:
1014: buffer_init(&m);
1015:
1016: if (ssh_msg_recv(fd, &m) == -1)
1017: fatal("%s: ssh_msg_recv failed", __func__);
1018: if (buffer_get_char(&m) != 0)
1019: fatal("%s: rexec version mismatch", __func__);
1020:
1021: cp = buffer_get_string(&m, &len);
1022: if (conf != NULL)
1023: buffer_append(conf, cp, len + 1);
1.402 djm 1024: free(cp);
1.294 djm 1025:
1026: if (buffer_get_int(&m)) {
1.426 markus 1027: #ifdef WITH_SSH1
1.294 djm 1028: if (sensitive_data.server_key != NULL)
1029: key_free(sensitive_data.server_key);
1030: sensitive_data.server_key = key_new_private(KEY_RSA1);
1031: buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
1032: buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
1033: buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
1034: buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
1035: buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
1036: buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
1.427 djm 1037: if (rsa_generate_additional_parameters(
1038: sensitive_data.server_key->rsa) != 0)
1039: fatal("%s: rsa_generate_additional_parameters "
1040: "error", __func__);
1.426 markus 1041: #else
1042: fatal("ssh1 not supported");
1043: #endif
1.294 djm 1044: }
1045: buffer_free(&m);
1046:
1047: debug3("%s: done", __func__);
1048: }
1049:
1.345 djm 1050: /* Accept a connection from inetd */
1051: static void
1052: server_accept_inetd(int *sock_in, int *sock_out)
1053: {
1054: int fd;
1055:
1056: startup_pipe = -1;
1057: if (rexeced_flag) {
1058: close(REEXEC_CONFIG_PASS_FD);
1059: *sock_in = *sock_out = dup(STDIN_FILENO);
1060: if (!debug_flag) {
1061: startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
1062: close(REEXEC_STARTUP_PIPE_FD);
1063: }
1064: } else {
1065: *sock_in = dup(STDIN_FILENO);
1066: *sock_out = dup(STDOUT_FILENO);
1067: }
1068: /*
1069: * We intentionally do not close the descriptors 0, 1, and 2
1070: * as our code for setting the descriptors won't work if
1071: * ttyfd happens to be one of those.
1072: */
1073: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1074: dup2(fd, STDIN_FILENO);
1075: dup2(fd, STDOUT_FILENO);
1.403 dtucker 1076: if (!log_stderr)
1077: dup2(fd, STDERR_FILENO);
1078: if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1.345 djm 1079: close(fd);
1080: }
1081: debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
1082: }
1083:
1084: /*
1085: * Listen for TCP connections
1086: */
1087: static void
1088: server_listen(void)
1089: {
1090: int ret, listen_sock, on = 1;
1091: struct addrinfo *ai;
1092: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1093:
1094: for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1095: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1096: continue;
1097: if (num_listen_socks >= MAX_LISTEN_SOCKS)
1098: fatal("Too many listen sockets. "
1099: "Enlarge MAX_LISTEN_SOCKS");
1100: if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
1101: ntop, sizeof(ntop), strport, sizeof(strport),
1102: NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
1103: error("getnameinfo failed: %.100s",
1.352 dtucker 1104: ssh_gai_strerror(ret));
1.345 djm 1105: continue;
1106: }
1107: /* Create socket for listening. */
1.370 dtucker 1108: listen_sock = socket(ai->ai_family, ai->ai_socktype,
1109: ai->ai_protocol);
1.345 djm 1110: if (listen_sock < 0) {
1111: /* kernel may not support ipv6 */
1112: verbose("socket: %.100s", strerror(errno));
1113: continue;
1114: }
1115: if (set_nonblock(listen_sock) == -1) {
1116: close(listen_sock);
1117: continue;
1118: }
1119: /*
1120: * Set socket options.
1121: * Allow local port reuse in TIME_WAIT.
1122: */
1123: if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1124: &on, sizeof(on)) == -1)
1125: error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1126:
1127: debug("Bind to port %s on %s.", strport, ntop);
1128:
1129: /* Bind the socket to the desired port. */
1130: if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1131: error("Bind to port %s on %s failed: %.200s.",
1132: strport, ntop, strerror(errno));
1133: close(listen_sock);
1134: continue;
1135: }
1136: listen_socks[num_listen_socks] = listen_sock;
1137: num_listen_socks++;
1138:
1139: /* Start listening on the port. */
1140: if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1141: fatal("listen on [%s]:%s: %.100s",
1142: ntop, strport, strerror(errno));
1143: logit("Server listening on %s port %s.", ntop, strport);
1144: }
1145: freeaddrinfo(options.listen_addrs);
1146:
1147: if (!num_listen_socks)
1148: fatal("Cannot bind any address.");
1149: }
1150:
1151: /*
1152: * The main TCP accept loop. Note that, for the non-debug case, returns
1153: * from this function are in a forked subprocess.
1154: */
1155: static void
1156: server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1157: {
1158: fd_set *fdset;
1159: int i, j, ret, maxfd;
1160: int key_used = 0, startups = 0;
1161: int startup_p[2] = { -1 , -1 };
1162: struct sockaddr_storage from;
1163: socklen_t fromlen;
1164: pid_t pid;
1165:
1166: /* setup fd set for accept */
1167: fdset = NULL;
1168: maxfd = 0;
1169: for (i = 0; i < num_listen_socks; i++)
1170: if (listen_socks[i] > maxfd)
1171: maxfd = listen_socks[i];
1172: /* pipes connected to unauthenticated childs */
1173: startup_pipes = xcalloc(options.max_startups, sizeof(int));
1174: for (i = 0; i < options.max_startups; i++)
1175: startup_pipes[i] = -1;
1176:
1177: /*
1178: * Stay listening for connections until the system crashes or
1179: * the daemon is killed with a signal.
1180: */
1181: for (;;) {
1182: if (received_sighup)
1183: sighup_restart();
1184: if (fdset != NULL)
1.402 djm 1185: free(fdset);
1.345 djm 1186: fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS),
1187: sizeof(fd_mask));
1188:
1189: for (i = 0; i < num_listen_socks; i++)
1190: FD_SET(listen_socks[i], fdset);
1191: for (i = 0; i < options.max_startups; i++)
1192: if (startup_pipes[i] != -1)
1193: FD_SET(startup_pipes[i], fdset);
1194:
1195: /* Wait in select until there is a connection. */
1196: ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1197: if (ret < 0 && errno != EINTR)
1198: error("select: %.100s", strerror(errno));
1199: if (received_sigterm) {
1200: logit("Received signal %d; terminating.",
1201: (int) received_sigterm);
1202: close_listen_socks();
1.430 djm 1203: if (options.pid_file != NULL)
1204: unlink(options.pid_file);
1.382 djm 1205: exit(received_sigterm == SIGTERM ? 0 : 255);
1.345 djm 1206: }
1207: if (key_used && key_do_regen) {
1208: generate_ephemeral_server_key();
1209: key_used = 0;
1210: key_do_regen = 0;
1211: }
1212: if (ret < 0)
1213: continue;
1214:
1215: for (i = 0; i < options.max_startups; i++)
1216: if (startup_pipes[i] != -1 &&
1217: FD_ISSET(startup_pipes[i], fdset)) {
1218: /*
1219: * the read end of the pipe is ready
1220: * if the child has closed the pipe
1221: * after successful authentication
1222: * or if the child has died
1223: */
1224: close(startup_pipes[i]);
1225: startup_pipes[i] = -1;
1226: startups--;
1227: }
1228: for (i = 0; i < num_listen_socks; i++) {
1229: if (!FD_ISSET(listen_socks[i], fdset))
1230: continue;
1231: fromlen = sizeof(from);
1232: *newsock = accept(listen_socks[i],
1233: (struct sockaddr *)&from, &fromlen);
1234: if (*newsock < 0) {
1.398 markus 1235: if (errno != EINTR && errno != EWOULDBLOCK &&
1236: errno != ECONNABORTED)
1.389 djm 1237: error("accept: %.100s",
1238: strerror(errno));
1239: if (errno == EMFILE || errno == ENFILE)
1240: usleep(100 * 1000);
1.345 djm 1241: continue;
1242: }
1243: if (unset_nonblock(*newsock) == -1) {
1244: close(*newsock);
1245: continue;
1246: }
1247: if (drop_connection(startups) == 1) {
1248: debug("drop connection #%d", startups);
1249: close(*newsock);
1250: continue;
1251: }
1252: if (pipe(startup_p) == -1) {
1253: close(*newsock);
1254: continue;
1255: }
1256:
1257: if (rexec_flag && socketpair(AF_UNIX,
1258: SOCK_STREAM, 0, config_s) == -1) {
1259: error("reexec socketpair: %s",
1260: strerror(errno));
1261: close(*newsock);
1262: close(startup_p[0]);
1263: close(startup_p[1]);
1264: continue;
1265: }
1266:
1267: for (j = 0; j < options.max_startups; j++)
1268: if (startup_pipes[j] == -1) {
1269: startup_pipes[j] = startup_p[0];
1270: if (maxfd < startup_p[0])
1271: maxfd = startup_p[0];
1272: startups++;
1273: break;
1274: }
1275:
1276: /*
1277: * Got connection. Fork a child to handle it, unless
1278: * we are in debugging mode.
1279: */
1280: if (debug_flag) {
1281: /*
1282: * In debugging mode. Close the listening
1283: * socket, and start processing the
1284: * connection without forking.
1285: */
1286: debug("Server will not fork when running in debugging mode.");
1287: close_listen_socks();
1288: *sock_in = *newsock;
1289: *sock_out = *newsock;
1290: close(startup_p[0]);
1291: close(startup_p[1]);
1292: startup_pipe = -1;
1293: pid = getpid();
1294: if (rexec_flag) {
1295: send_rexec_state(config_s[0],
1296: &cfg);
1297: close(config_s[0]);
1298: }
1299: break;
1300: }
1301:
1302: /*
1303: * Normal production daemon. Fork, and have
1304: * the child process the connection. The
1305: * parent continues listening.
1306: */
1307: if ((pid = fork()) == 0) {
1308: /*
1309: * Child. Close the listening and
1310: * max_startup sockets. Start using
1311: * the accepted socket. Reinitialize
1312: * logging (since our pid has changed).
1313: * We break out of the loop to handle
1314: * the connection.
1315: */
1316: startup_pipe = startup_p[1];
1317: close_startup_pipes();
1318: close_listen_socks();
1319: *sock_in = *newsock;
1320: *sock_out = *newsock;
1321: log_init(__progname,
1322: options.log_level,
1323: options.log_facility,
1324: log_stderr);
1325: if (rexec_flag)
1326: close(config_s[0]);
1327: break;
1328: }
1329:
1330: /* Parent. Stay in the loop. */
1331: if (pid < 0)
1332: error("fork: %.100s", strerror(errno));
1333: else
1334: debug("Forked child %ld.", (long)pid);
1335:
1336: close(startup_p[1]);
1337:
1338: if (rexec_flag) {
1339: send_rexec_state(config_s[0], &cfg);
1340: close(config_s[0]);
1341: close(config_s[1]);
1342: }
1343:
1344: /*
1345: * Mark that the key has been used (it
1346: * was "given" to the child).
1347: */
1348: if ((options.protocol & SSH_PROTO_1) &&
1349: key_used == 0) {
1350: /* Schedule server key regeneration alarm. */
1351: signal(SIGALRM, key_regeneration_alarm);
1352: alarm(options.key_regeneration_time);
1353: key_used = 1;
1354: }
1355:
1356: close(*newsock);
1357: }
1358:
1359: /* child process check (or debug mode) */
1360: if (num_listen_socks < 0)
1361: break;
1362: }
1363: }
1364:
1365:
1.65 deraadt 1366: /*
1367: * Main program for the daemon.
1368: */
1.2 provos 1369: int
1370: main(int ac, char **av)
1.1 deraadt 1371: {
1.64 markus 1372: extern char *optarg;
1373: extern int optind;
1.432 djm 1374: int r, opt, i, j, on = 1;
1.297 avsm 1375: int sock_in = -1, sock_out = -1, newsock = -1;
1.64 markus 1376: const char *remote_ip;
1377: int remote_port;
1.399 dtucker 1378: char *line, *logfile = NULL;
1.345 djm 1379: int config_s[2] = { -1 , -1 };
1.396 djm 1380: u_int n;
1.364 markus 1381: u_int64_t ibytes, obytes;
1.362 dtucker 1382: mode_t new_umask;
1.278 markus 1383: Key *key;
1.404 markus 1384: Key *pubkey;
1385: int keytype;
1.230 provos 1386: Authctxt *authctxt;
1.391 dtucker 1387: struct connection_info *connection_info = get_connection_info(0, 0);
1.64 markus 1388:
1.138 markus 1389: /* Save argv. */
1.64 markus 1390: saved_argv = av;
1.294 djm 1391: rexec_argc = ac;
1.313 djm 1392:
1393: /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1394: sanitise_stdfd();
1.64 markus 1395:
1396: /* Initialize configuration options to their default values. */
1397: initialize_server_options(&options);
1398:
1399: /* Parse command-line arguments. */
1.399 dtucker 1400: while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeE:iqrtQRT46")) != -1) {
1.64 markus 1401: switch (opt) {
1.75 markus 1402: case '4':
1.305 djm 1403: options.address_family = AF_INET;
1.75 markus 1404: break;
1405: case '6':
1.305 djm 1406: options.address_family = AF_INET6;
1.75 markus 1407: break;
1.64 markus 1408: case 'f':
1409: config_file_name = optarg;
1410: break;
1.373 djm 1411: case 'c':
1412: if (options.num_host_cert_files >= MAX_HOSTCERTS) {
1413: fprintf(stderr, "too many host certificates.\n");
1414: exit(1);
1415: }
1416: options.host_cert_files[options.num_host_cert_files++] =
1417: derelativise_path(optarg);
1418: break;
1.64 markus 1419: case 'd':
1.273 markus 1420: if (debug_flag == 0) {
1.127 markus 1421: debug_flag = 1;
1422: options.log_level = SYSLOG_LEVEL_DEBUG1;
1.273 markus 1423: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1.127 markus 1424: options.log_level++;
1.64 markus 1425: break;
1.135 markus 1426: case 'D':
1427: no_daemon_flag = 1;
1.192 lebel 1428: break;
1.399 dtucker 1429: case 'E':
1430: logfile = xstrdup(optarg);
1431: /* FALLTHROUGH */
1.192 lebel 1432: case 'e':
1433: log_stderr = 1;
1.135 markus 1434: break;
1.64 markus 1435: case 'i':
1436: inetd_flag = 1;
1437: break;
1.294 djm 1438: case 'r':
1439: rexec_flag = 0;
1440: break;
1441: case 'R':
1442: rexeced_flag = 1;
1443: inetd_flag = 1;
1444: break;
1.64 markus 1445: case 'Q':
1.158 markus 1446: /* ignored */
1.64 markus 1447: break;
1448: case 'q':
1449: options.log_level = SYSLOG_LEVEL_QUIET;
1450: break;
1451: case 'b':
1.327 deraadt 1452: options.server_key_bits = (int)strtonum(optarg, 256,
1453: 32768, NULL);
1.64 markus 1454: break;
1455: case 'p':
1.75 markus 1456: options.ports_from_cmdline = 1;
1.127 markus 1457: if (options.num_ports >= MAX_PORTS) {
1458: fprintf(stderr, "too many ports.\n");
1459: exit(1);
1460: }
1.193 stevesk 1461: options.ports[options.num_ports++] = a2port(optarg);
1.366 djm 1462: if (options.ports[options.num_ports-1] <= 0) {
1.193 stevesk 1463: fprintf(stderr, "Bad port number.\n");
1464: exit(1);
1465: }
1.64 markus 1466: break;
1467: case 'g':
1.197 stevesk 1468: if ((options.login_grace_time = convtime(optarg)) == -1) {
1469: fprintf(stderr, "Invalid login grace time.\n");
1470: exit(1);
1471: }
1.64 markus 1472: break;
1473: case 'k':
1.197 stevesk 1474: if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1475: fprintf(stderr, "Invalid key regeneration interval.\n");
1476: exit(1);
1477: }
1.64 markus 1478: break;
1479: case 'h':
1.134 markus 1480: if (options.num_host_key_files >= MAX_HOSTKEYS) {
1481: fprintf(stderr, "too many host keys.\n");
1482: exit(1);
1483: }
1.371 djm 1484: options.host_key_files[options.num_host_key_files++] =
1485: derelativise_path(optarg);
1.64 markus 1486: break;
1.203 stevesk 1487: case 't':
1488: test_flag = 1;
1489: break;
1.358 dtucker 1490: case 'T':
1491: test_flag = 2;
1492: break;
1493: case 'C':
1.391 dtucker 1494: if (parse_server_match_testspec(connection_info,
1495: optarg) == -1)
1496: exit(1);
1.358 dtucker 1497: break;
1.125 markus 1498: case 'u':
1.438 deraadt 1499: utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1500: if (utmp_len > HOST_NAME_MAX+1) {
1.257 stevesk 1501: fprintf(stderr, "Invalid utmp length.\n");
1502: exit(1);
1503: }
1.125 markus 1504: break;
1.215 markus 1505: case 'o':
1.283 markus 1506: line = xstrdup(optarg);
1507: if (process_server_config_line(&options, line,
1.391 dtucker 1508: "command-line", 0, NULL, NULL) != 0)
1.217 deraadt 1509: exit(1);
1.402 djm 1510: free(line);
1.215 markus 1511: break;
1.64 markus 1512: case '?':
1513: default:
1.215 markus 1514: usage();
1515: break;
1.64 markus 1516: }
1517: }
1.294 djm 1518: if (rexeced_flag || inetd_flag)
1519: rexec_flag = 0;
1.355 mbalmer 1520: if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1.294 djm 1521: fatal("sshd re-exec requires execution with an absolute path");
1522: if (rexeced_flag)
1.296 djm 1523: closefrom(REEXEC_MIN_FREE_FD);
1524: else
1525: closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1.294 djm 1526:
1.426 markus 1527: #ifdef WITH_OPENSSL
1.379 djm 1528: OpenSSL_add_all_algorithms();
1.426 markus 1529: #endif
1.64 markus 1530:
1.399 dtucker 1531: /* If requested, redirect the logs to the specified logfile. */
1532: if (logfile != NULL) {
1533: log_redirect_stderr_to(logfile);
1.402 djm 1534: free(logfile);
1.399 dtucker 1535: }
1.75 markus 1536: /*
1537: * Force logging to stderr until we have loaded the private host
1538: * key (unless started from inetd)
1539: */
1.138 markus 1540: log_init(__progname,
1.224 markus 1541: options.log_level == SYSLOG_LEVEL_NOT_SET ?
1542: SYSLOG_LEVEL_INFO : options.log_level,
1543: options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1544: SYSLOG_FACILITY_AUTH : options.log_facility,
1.261 markus 1545: log_stderr || !inetd_flag);
1.75 markus 1546:
1.294 djm 1547: sensitive_data.server_key = NULL;
1548: sensitive_data.ssh1_host_key = NULL;
1549: sensitive_data.have_ssh1_key = 0;
1550: sensitive_data.have_ssh2_key = 0;
1551:
1.358 dtucker 1552: /*
1553: * If we're doing an extended config test, make sure we have all of
1554: * the parameters we need. If we're not doing an extended test,
1555: * do not silently ignore connection test params.
1556: */
1.391 dtucker 1557: if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0)
1.358 dtucker 1558: fatal("user, host and addr are all required when testing "
1559: "Match configs");
1.391 dtucker 1560: if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0)
1.358 dtucker 1561: fatal("Config test connection parameter (-C) provided without "
1562: "test mode (-T)");
1563:
1.294 djm 1564: /* Fetch our configuration */
1565: buffer_init(&cfg);
1566: if (rexeced_flag)
1.296 djm 1567: recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
1.294 djm 1568: else
1569: load_server_config(config_file_name, &cfg);
1570:
1.337 dtucker 1571: parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1.391 dtucker 1572: &cfg, NULL);
1.64 markus 1573:
1574: /* Fill in default values for those options not explicitly set. */
1575: fill_default_server_options(&options);
1.350 dtucker 1576:
1577: /* challenge-response is implemented via keyboard interactive */
1578: if (options.challenge_response_authentication)
1579: options.kbd_interactive_authentication = 1;
1.395 djm 1580:
1581: /* Check that options are sensible */
1582: if (options.authorized_keys_command_user == NULL &&
1583: (options.authorized_keys_command != NULL &&
1584: strcasecmp(options.authorized_keys_command, "none") != 0))
1585: fatal("AuthorizedKeysCommand set without "
1586: "AuthorizedKeysCommandUser");
1.396 djm 1587:
1588: /*
1589: * Check whether there is any path through configured auth methods.
1590: * Unfortunately it is not possible to verify this generally before
1591: * daemonisation in the presence of Match block, but this catches
1592: * and warns for trivial misconfigurations that could break login.
1593: */
1594: if (options.num_auth_methods != 0) {
1595: if ((options.protocol & SSH_PROTO_1))
1596: fatal("AuthenticationMethods is not supported with "
1597: "SSH protocol 1");
1598: for (n = 0; n < options.num_auth_methods; n++) {
1599: if (auth2_methods_valid(options.auth_methods[n],
1600: 1) == 0)
1601: break;
1602: }
1603: if (n >= options.num_auth_methods)
1604: fatal("AuthenticationMethods cannot be satisfied by "
1605: "enabled authentication methods");
1606: }
1.305 djm 1607:
1.370 dtucker 1608: /* set default channel AF */
1.305 djm 1609: channel_set_af(options.address_family);
1.64 markus 1610:
1611: /* Check that there are no remaining arguments. */
1612: if (optind < ac) {
1613: fprintf(stderr, "Extra argument %s.\n", av[optind]);
1614: exit(1);
1615: }
1616:
1.397 dtucker 1617: debug("sshd version %s, %s", SSH_VERSION,
1.426 markus 1618: #ifdef WITH_OPENSSL
1619: SSLeay_version(SSLEAY_VERSION)
1620: #else
1621: "without OpenSSL"
1622: #endif
1623: );
1.64 markus 1624:
1.404 markus 1625: /* load host keys */
1.329 djm 1626: sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1.255 deraadt 1627: sizeof(Key *));
1.404 markus 1628: sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1629: sizeof(Key *));
1630:
1631: if (options.host_key_agent) {
1632: if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1633: setenv(SSH_AUTHSOCKET_ENV_NAME,
1634: options.host_key_agent, 1);
1.433 djm 1635: if ((r = ssh_get_authentication_socket(NULL)) == 0)
1636: have_agent = 1;
1637: else
1638: error("Could not connect to agent \"%s\": %s",
1639: options.host_key_agent, ssh_err(r));
1.404 markus 1640: }
1.134 markus 1641:
1.217 deraadt 1642: for (i = 0; i < options.num_host_key_files; i++) {
1.430 djm 1643: if (options.host_key_files[i] == NULL)
1644: continue;
1.179 markus 1645: key = key_load_private(options.host_key_files[i], "", NULL);
1.404 markus 1646: pubkey = key_load_public(options.host_key_files[i], NULL);
1.439 ! djm 1647: if (pubkey == NULL && key != NULL)
! 1648: pubkey = key_demote(key);
1.179 markus 1649: sensitive_data.host_keys[i] = key;
1.404 markus 1650: sensitive_data.host_pubkeys[i] = pubkey;
1651:
1652: if (key == NULL && pubkey != NULL && pubkey->type != KEY_RSA1 &&
1653: have_agent) {
1654: debug("will rely on agent for hostkey %s",
1655: options.host_key_files[i]);
1656: keytype = pubkey->type;
1657: } else if (key != NULL) {
1658: keytype = key->type;
1659: } else {
1.195 markus 1660: error("Could not load host key: %s",
1661: options.host_key_files[i]);
1.179 markus 1662: sensitive_data.host_keys[i] = NULL;
1.404 markus 1663: sensitive_data.host_pubkeys[i] = NULL;
1.134 markus 1664: continue;
1665: }
1.404 markus 1666:
1667: switch (keytype) {
1.134 markus 1668: case KEY_RSA1:
1669: sensitive_data.ssh1_host_key = key;
1670: sensitive_data.have_ssh1_key = 1;
1671: break;
1672: case KEY_RSA:
1673: case KEY_DSA:
1.378 djm 1674: case KEY_ECDSA:
1.412 markus 1675: case KEY_ED25519:
1.134 markus 1676: sensitive_data.have_ssh2_key = 1;
1677: break;
1678: }
1.404 markus 1679: debug("private host key: #%d type %d %s", i, keytype,
1680: key_type(key ? key : pubkey));
1.134 markus 1681: }
1682: if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
1.264 itojun 1683: logit("Disabling protocol version 1. Could not load host key");
1.108 markus 1684: options.protocol &= ~SSH_PROTO_1;
1685: }
1.134 markus 1686: if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1.264 itojun 1687: logit("Disabling protocol version 2. Could not load host key");
1.134 markus 1688: options.protocol &= ~SSH_PROTO_2;
1.108 markus 1689: }
1.162 stevesk 1690: if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1.264 itojun 1691: logit("sshd: no hostkeys available -- exiting.");
1.64 markus 1692: exit(1);
1693: }
1694:
1.373 djm 1695: /*
1696: * Load certificates. They are stored in an array at identical
1697: * indices to the public keys that they relate to.
1698: */
1699: sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1700: sizeof(Key *));
1701: for (i = 0; i < options.num_host_key_files; i++)
1702: sensitive_data.host_certificates[i] = NULL;
1703:
1704: for (i = 0; i < options.num_host_cert_files; i++) {
1.430 djm 1705: if (options.host_cert_files[i] == NULL)
1706: continue;
1.373 djm 1707: key = key_load_public(options.host_cert_files[i], NULL);
1708: if (key == NULL) {
1709: error("Could not load host certificate: %s",
1710: options.host_cert_files[i]);
1711: continue;
1712: }
1713: if (!key_is_cert(key)) {
1714: error("Certificate file is not a certificate: %s",
1715: options.host_cert_files[i]);
1716: key_free(key);
1717: continue;
1718: }
1719: /* Find matching private key */
1720: for (j = 0; j < options.num_host_key_files; j++) {
1721: if (key_equal_public(key,
1722: sensitive_data.host_keys[j])) {
1723: sensitive_data.host_certificates[j] = key;
1724: break;
1725: }
1726: }
1727: if (j >= options.num_host_key_files) {
1728: error("No matching private key for certificate: %s",
1729: options.host_cert_files[i]);
1730: key_free(key);
1731: continue;
1732: }
1733: sensitive_data.host_certificates[j] = key;
1734: debug("host certificate: #%d type %d %s", j, key->type,
1735: key_type(key));
1736: }
1.426 markus 1737:
1738: #ifdef WITH_SSH1
1.108 markus 1739: /* Check certain values for sanity. */
1740: if (options.protocol & SSH_PROTO_1) {
1741: if (options.server_key_bits < 512 ||
1742: options.server_key_bits > 32768) {
1743: fprintf(stderr, "Bad server key size.\n");
1744: exit(1);
1745: }
1746: /*
1747: * Check that server and host key lengths differ sufficiently. This
1748: * is necessary to make double encryption work with rsaref. Oh, I
1749: * hate software patents. I dont know if this can go? Niels
1750: */
1751: if (options.server_key_bits >
1.250 deraadt 1752: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1753: SSH_KEY_BITS_RESERVED && options.server_key_bits <
1754: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1755: SSH_KEY_BITS_RESERVED) {
1.108 markus 1756: options.server_key_bits =
1.250 deraadt 1757: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1758: SSH_KEY_BITS_RESERVED;
1.108 markus 1759: debug("Forcing server key to %d bits to make it differ from host key.",
1760: options.server_key_bits);
1761: }
1.244 markus 1762: }
1.426 markus 1763: #endif
1.244 markus 1764:
1765: if (use_privsep) {
1766: struct stat st;
1767:
1.327 deraadt 1768: if (getpwnam(SSH_PRIVSEP_USER) == NULL)
1.244 markus 1769: fatal("Privilege separation user %s does not exist",
1770: SSH_PRIVSEP_USER);
1771: if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1772: (S_ISDIR(st.st_mode) == 0))
1773: fatal("Missing privilege separation directory: %s",
1.247 stevesk 1774: _PATH_PRIVSEP_CHROOT_DIR);
1775: if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1.262 markus 1776: fatal("%s must be owned by root and not group or "
1777: "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1.358 dtucker 1778: }
1779:
1780: if (test_flag > 1) {
1.391 dtucker 1781: if (server_match_spec_complete(connection_info) == 1)
1782: parse_server_match_config(&options, connection_info);
1.358 dtucker 1783: dump_config(&options);
1.108 markus 1784: }
1.203 stevesk 1785:
1786: /* Configuration looks good, so exit if in test mode. */
1787: if (test_flag)
1788: exit(0);
1.108 markus 1789:
1.294 djm 1790: if (rexec_flag) {
1.329 djm 1791: rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
1.294 djm 1792: for (i = 0; i < rexec_argc; i++) {
1793: debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1794: rexec_argv[i] = saved_argv[i];
1795: }
1796: rexec_argv[rexec_argc] = "-R";
1797: rexec_argv[rexec_argc + 1] = NULL;
1798: }
1.362 dtucker 1799:
1800: /* Ensure that umask disallows at least group and world write */
1801: new_umask = umask(0077) | 0022;
1802: (void) umask(new_umask);
1.294 djm 1803:
1.108 markus 1804: /* Initialize the log (it is reinitialized below in case we forked). */
1.306 dtucker 1805: if (debug_flag && (!inetd_flag || rexeced_flag))
1.64 markus 1806: log_stderr = 1;
1.138 markus 1807: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1808:
1.108 markus 1809: /*
1810: * If not in debugging mode, and not started from inetd, disconnect
1811: * from the controlling terminal, and fork. The original process
1812: * exits.
1813: */
1.135 markus 1814: if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1.64 markus 1815: int fd;
1.345 djm 1816:
1.64 markus 1817: if (daemon(0, 0) < 0)
1818: fatal("daemon() failed: %.200s", strerror(errno));
1819:
1820: /* Disconnect from the controlling tty. */
1.165 itojun 1821: fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1.64 markus 1822: if (fd >= 0) {
1823: (void) ioctl(fd, TIOCNOTTY, NULL);
1824: close(fd);
1825: }
1826: }
1827: /* Reinitialize the log (because of the fork above). */
1.138 markus 1828: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1829:
1830: /* Chdir to the root directory so that the current disk can be
1831: unmounted if desired. */
1.401 dtucker 1832: if (chdir("/") == -1)
1833: error("chdir(\"/\"): %s", strerror(errno));
1.217 deraadt 1834:
1.178 markus 1835: /* ignore SIGPIPE */
1836: signal(SIGPIPE, SIG_IGN);
1.64 markus 1837:
1.345 djm 1838: /* Get a connection, either from inetd or a listening TCP socket */
1.64 markus 1839: if (inetd_flag) {
1.345 djm 1840: server_accept_inetd(&sock_in, &sock_out);
1.64 markus 1841: } else {
1.345 djm 1842: server_listen();
1.75 markus 1843:
1.201 markus 1844: if (options.protocol & SSH_PROTO_1)
1845: generate_ephemeral_server_key();
1846:
1847: signal(SIGHUP, sighup_handler);
1.345 djm 1848: signal(SIGCHLD, main_sigchld_handler);
1.201 markus 1849: signal(SIGTERM, sigterm_handler);
1850: signal(SIGQUIT, sigterm_handler);
1851:
1.345 djm 1852: /*
1853: * Write out the pid file after the sigterm handler
1854: * is setup and the listen sockets are bound
1855: */
1.430 djm 1856: if (options.pid_file != NULL && !debug_flag) {
1.345 djm 1857: FILE *f = fopen(options.pid_file, "w");
1.201 markus 1858:
1.270 djm 1859: if (f == NULL) {
1860: error("Couldn't create pid file \"%s\": %s",
1861: options.pid_file, strerror(errno));
1862: } else {
1.245 mpech 1863: fprintf(f, "%ld\n", (long) getpid());
1.64 markus 1864: fclose(f);
1865: }
1866: }
1867:
1.345 djm 1868: /* Accept a connection and return in a forked child */
1869: server_accept_loop(&sock_in, &sock_out,
1870: &newsock, config_s);
1.1 deraadt 1871: }
1872:
1.64 markus 1873: /* This is the child processing a new connection. */
1.288 markus 1874: setproctitle("%s", "[accepted]");
1.294 djm 1875:
1.300 markus 1876: /*
1877: * Create a new session and process group since the 4.4BSD
1878: * setlogin() affects the entire process group. We don't
1879: * want the child to be able to affect the parent.
1880: */
1881: if (!debug_flag && !inetd_flag && setsid() < 0)
1882: error("setsid: %.100s", strerror(errno));
1883:
1.294 djm 1884: if (rexec_flag) {
1885: int fd;
1886:
1.296 djm 1887: debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1888: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1889: dup2(newsock, STDIN_FILENO);
1890: dup2(STDIN_FILENO, STDOUT_FILENO);
1891: if (startup_pipe == -1)
1.296 djm 1892: close(REEXEC_STARTUP_PIPE_FD);
1.407 djm 1893: else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
1.296 djm 1894: dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
1.407 djm 1895: close(startup_pipe);
1896: startup_pipe = REEXEC_STARTUP_PIPE_FD;
1897: }
1.294 djm 1898:
1.296 djm 1899: dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
1.294 djm 1900: close(config_s[1]);
1.296 djm 1901:
1.294 djm 1902: execv(rexec_argv[0], rexec_argv);
1903:
1904: /* Reexec has failed, fall back and continue */
1905: error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
1.296 djm 1906: recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
1.294 djm 1907: log_init(__progname, options.log_level,
1908: options.log_facility, log_stderr);
1909:
1910: /* Clean up fds */
1.296 djm 1911: close(REEXEC_CONFIG_PASS_FD);
1912: newsock = sock_out = sock_in = dup(STDIN_FILENO);
1.294 djm 1913: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1914: dup2(fd, STDIN_FILENO);
1915: dup2(fd, STDOUT_FILENO);
1916: if (fd > STDERR_FILENO)
1917: close(fd);
1918: }
1.296 djm 1919: debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1920: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1921: }
1.372 djm 1922:
1923: /* Executed child processes don't need these. */
1924: fcntl(sock_out, F_SETFD, FD_CLOEXEC);
1925: fcntl(sock_in, F_SETFD, FD_CLOEXEC);
1.64 markus 1926:
1.66 markus 1927: /*
1928: * Disable the key regeneration alarm. We will not regenerate the
1929: * key since we are no longer in a position to give it to anyone. We
1930: * will not restart on SIGHUP since it no longer makes sense.
1931: */
1.64 markus 1932: alarm(0);
1933: signal(SIGALRM, SIG_DFL);
1934: signal(SIGHUP, SIG_DFL);
1935: signal(SIGTERM, SIG_DFL);
1936: signal(SIGQUIT, SIG_DFL);
1937: signal(SIGCHLD, SIG_DFL);
1.150 markus 1938:
1.66 markus 1939: /*
1940: * Register our connection. This turns encryption off because we do
1941: * not have a key.
1942: */
1.64 markus 1943: packet_set_connection(sock_in, sock_out);
1.312 markus 1944: packet_set_server();
1.309 djm 1945:
1946: /* Set SO_KEEPALIVE if requested. */
1947: if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1948: setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1949: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.1 deraadt 1950:
1.310 markus 1951: if ((remote_port = get_remote_port()) < 0) {
1952: debug("get_remote_port failed");
1953: cleanup_exit(255);
1954: }
1.316 dtucker 1955:
1956: /*
1957: * We use get_canonical_hostname with usedns = 0 instead of
1958: * get_remote_ipaddr here so IP options will be checked.
1959: */
1.331 markus 1960: (void) get_canonical_hostname(0);
1961: /*
1962: * The rest of the code depends on the fact that
1963: * get_remote_ipaddr() caches the remote ip, even if
1964: * the socket goes away.
1965: */
1966: remote_ip = get_remote_ipaddr();
1.209 markus 1967:
1.64 markus 1968: /* Log the connection. */
1.409 djm 1969: verbose("Connection from %s port %d on %s port %d",
1970: remote_ip, remote_port,
1971: get_local_ipaddr(sock_in), get_local_port());
1.1 deraadt 1972:
1.66 markus 1973: /*
1.317 djm 1974: * We don't want to listen forever unless the other side
1.66 markus 1975: * successfully authenticates itself. So we set up an alarm which is
1976: * cleared after successful authentication. A limit of zero
1.317 djm 1977: * indicates no limit. Note that we don't set the alarm in debugging
1.66 markus 1978: * mode; it is just annoying to have the server exit just when you
1979: * are about to discover the bug.
1980: */
1.64 markus 1981: signal(SIGALRM, grace_alarm_handler);
1982: if (!debug_flag)
1983: alarm(options.login_grace_time);
1984:
1.96 markus 1985: sshd_exchange_identification(sock_in, sock_out);
1.353 dtucker 1986:
1987: /* In inetd mode, generate ephemeral key only for proto 1 connections */
1988: if (!compat20 && inetd_flag && sensitive_data.server_key == NULL)
1989: generate_ephemeral_server_key();
1.275 markus 1990:
1.64 markus 1991: packet_set_nonblocking();
1.1 deraadt 1992:
1.278 markus 1993: /* allocate authentication context */
1.329 djm 1994: authctxt = xcalloc(1, sizeof(*authctxt));
1.278 markus 1995:
1996: /* XXX global for cleanup, access from other modules */
1997: the_authctxt = authctxt;
1998:
1.307 otto 1999: /* prepare buffer to collect messages to display to user after login */
2000: buffer_init(&loginmsg);
1.374 dtucker 2001: auth_debug_reset();
1.307 otto 2002:
1.404 markus 2003: if (use_privsep) {
1.278 markus 2004: if (privsep_preauth(authctxt) == 1)
1.237 markus 2005: goto authenticated;
1.432 djm 2006: } else if (compat20 && have_agent) {
2007: if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
2008: error("Unable to get agent socket: %s", ssh_err(r));
1.433 djm 2009: have_agent = 0;
1.432 djm 2010: }
2011: }
1.231 provos 2012:
1.77 markus 2013: /* perform the key exchange */
2014: /* authenticate user and start session */
1.98 markus 2015: if (compat20) {
2016: do_ssh2_kex();
1.278 markus 2017: do_authentication2(authctxt);
1.98 markus 2018: } else {
1.426 markus 2019: #ifdef WITH_SSH1
1.98 markus 2020: do_ssh1_kex();
1.278 markus 2021: do_authentication(authctxt);
1.426 markus 2022: #else
2023: fatal("ssh1 not supported");
2024: #endif
1.98 markus 2025: }
1.237 markus 2026: /*
2027: * If we use privilege separation, the unprivileged child transfers
2028: * the current keystate and exits
2029: */
2030: if (use_privsep) {
1.242 mouring 2031: mm_send_keystate(pmonitor);
1.231 provos 2032: exit(0);
1.237 markus 2033: }
1.231 provos 2034:
2035: authenticated:
1.318 djm 2036: /*
2037: * Cancel the alarm we set to limit the time taken for
2038: * authentication.
2039: */
2040: alarm(0);
2041: signal(SIGALRM, SIG_DFL);
1.347 markus 2042: authctxt->authenticated = 1;
1.318 djm 2043: if (startup_pipe != -1) {
2044: close(startup_pipe);
2045: startup_pipe = -1;
2046: }
2047:
1.234 markus 2048: /*
1.231 provos 2049: * In privilege separation, we fork another child and prepare
2050: * file descriptor passing.
2051: */
2052: if (use_privsep) {
1.237 markus 2053: privsep_postauth(authctxt);
2054: /* the monitor process [priv] will not return */
1.231 provos 2055: if (!compat20)
2056: destroy_sensitive_data();
2057: }
1.360 dtucker 2058:
2059: packet_set_timeout(options.client_alive_interval,
2060: options.client_alive_count_max);
1.439 ! djm 2061:
! 2062: /* Try to send all our hostkeys to the client */
! 2063: if (compat20)
! 2064: notify_hostkeys(active_state);
1.230 provos 2065:
1.278 markus 2066: /* Start session. */
1.230 provos 2067: do_authenticated(authctxt);
2068:
1.64 markus 2069: /* The connection has been terminated. */
1.434 markus 2070: packet_get_bytes(&ibytes, &obytes);
1.381 djm 2071: verbose("Transferred: sent %llu, received %llu bytes",
2072: (unsigned long long)obytes, (unsigned long long)ibytes);
1.364 markus 2073:
2074: verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
1.64 markus 2075: packet_close();
1.231 provos 2076:
2077: if (use_privsep)
2078: mm_terminate();
2079:
1.64 markus 2080: exit(0);
1.1 deraadt 2081: }
2082:
1.426 markus 2083: #ifdef WITH_SSH1
1.65 deraadt 2084: /*
1.229 markus 2085: * Decrypt session_key_int using our private server key and private host key
2086: * (key with larger modulus first).
2087: */
1.231 provos 2088: int
1.229 markus 2089: ssh1_session_key(BIGNUM *session_key_int)
2090: {
2091: int rsafail = 0;
2092:
1.327 deraadt 2093: if (BN_cmp(sensitive_data.server_key->rsa->n,
2094: sensitive_data.ssh1_host_key->rsa->n) > 0) {
1.229 markus 2095: /* Server key has bigger modulus. */
2096: if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1.327 deraadt 2097: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
2098: SSH_KEY_BITS_RESERVED) {
2099: fatal("do_connection: %s: "
2100: "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1.229 markus 2101: get_remote_ipaddr(),
2102: BN_num_bits(sensitive_data.server_key->rsa->n),
2103: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
2104: SSH_KEY_BITS_RESERVED);
2105: }
2106: if (rsa_private_decrypt(session_key_int, session_key_int,
1.427 djm 2107: sensitive_data.server_key->rsa) != 0)
1.229 markus 2108: rsafail++;
2109: if (rsa_private_decrypt(session_key_int, session_key_int,
1.427 djm 2110: sensitive_data.ssh1_host_key->rsa) != 0)
1.229 markus 2111: rsafail++;
2112: } else {
2113: /* Host key has bigger modulus (or they are equal). */
2114: if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1.327 deraadt 2115: BN_num_bits(sensitive_data.server_key->rsa->n) +
2116: SSH_KEY_BITS_RESERVED) {
2117: fatal("do_connection: %s: "
2118: "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1.229 markus 2119: get_remote_ipaddr(),
2120: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
2121: BN_num_bits(sensitive_data.server_key->rsa->n),
2122: SSH_KEY_BITS_RESERVED);
2123: }
2124: if (rsa_private_decrypt(session_key_int, session_key_int,
1.427 djm 2125: sensitive_data.ssh1_host_key->rsa) != 0)
1.229 markus 2126: rsafail++;
2127: if (rsa_private_decrypt(session_key_int, session_key_int,
1.427 djm 2128: sensitive_data.server_key->rsa) != 0)
1.229 markus 2129: rsafail++;
2130: }
2131: return (rsafail);
2132: }
1.426 markus 2133:
1.229 markus 2134: /*
1.77 markus 2135: * SSH1 key exchange
1.65 deraadt 2136: */
1.200 itojun 2137: static void
1.142 markus 2138: do_ssh1_kex(void)
1.1 deraadt 2139: {
1.64 markus 2140: int i, len;
1.159 markus 2141: int rsafail = 0;
1.431 tedu 2142: BIGNUM *session_key_int, *fake_key_int, *real_key_int;
1.140 markus 2143: u_char session_key[SSH_SESSION_KEY_LENGTH];
1.431 tedu 2144: u_char fake_key_bytes[4096 / 8];
2145: size_t fake_key_len;
1.140 markus 2146: u_char cookie[8];
2147: u_int cipher_type, auth_mask, protocol_flags;
1.64 markus 2148:
1.66 markus 2149: /*
2150: * Generate check bytes that the client must send back in the user
2151: * packet in order for it to be accepted; this is used to defy ip
2152: * spoofing attacks. Note that this only works against somebody
2153: * doing IP spoofing from a remote machine; any machine on the local
2154: * network can still see outgoing packets and catch the random
2155: * cookie. This only affects rhosts authentication, and this is one
2156: * of the reasons why it is inherently insecure.
2157: */
1.356 djm 2158: arc4random_buf(cookie, sizeof(cookie));
1.64 markus 2159:
1.66 markus 2160: /*
2161: * Send our public key. We include in the packet 64 bits of random
2162: * data that must be matched in the reply in order to prevent IP
2163: * spoofing.
2164: */
1.64 markus 2165: packet_start(SSH_SMSG_PUBLIC_KEY);
2166: for (i = 0; i < 8; i++)
1.77 markus 2167: packet_put_char(cookie[i]);
1.64 markus 2168:
2169: /* Store our public server RSA key. */
1.134 markus 2170: packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
2171: packet_put_bignum(sensitive_data.server_key->rsa->e);
2172: packet_put_bignum(sensitive_data.server_key->rsa->n);
1.64 markus 2173:
2174: /* Store our public host RSA key. */
1.134 markus 2175: packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
2176: packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
2177: packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1.64 markus 2178:
2179: /* Put protocol flags. */
2180: packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
2181:
2182: /* Declare which ciphers we support. */
1.131 markus 2183: packet_put_int(cipher_mask_ssh1(0));
1.64 markus 2184:
2185: /* Declare supported authentication types. */
2186: auth_mask = 0;
2187: if (options.rhosts_rsa_authentication)
2188: auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
2189: if (options.rsa_authentication)
2190: auth_mask |= 1 << SSH_AUTH_RSA;
1.196 markus 2191: if (options.challenge_response_authentication == 1)
1.64 markus 2192: auth_mask |= 1 << SSH_AUTH_TIS;
2193: if (options.password_authentication)
2194: auth_mask |= 1 << SSH_AUTH_PASSWORD;
2195: packet_put_int(auth_mask);
2196:
2197: /* Send the packet and wait for it to be sent. */
2198: packet_send();
2199: packet_write_wait();
2200:
1.134 markus 2201: debug("Sent %d bit server key and %d bit host key.",
2202: BN_num_bits(sensitive_data.server_key->rsa->n),
2203: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1.64 markus 2204:
2205: /* Read clients reply (cipher type and session key). */
1.222 markus 2206: packet_read_expect(SSH_CMSG_SESSION_KEY);
1.64 markus 2207:
1.69 markus 2208: /* Get cipher type and check whether we accept this. */
1.64 markus 2209: cipher_type = packet_get_char();
1.69 markus 2210:
1.131 markus 2211: if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1.69 markus 2212: packet_disconnect("Warning: client selects unsupported cipher.");
1.64 markus 2213:
2214: /* Get check bytes from the packet. These must match those we
2215: sent earlier with the public key packet. */
2216: for (i = 0; i < 8; i++)
1.77 markus 2217: if (cookie[i] != packet_get_char())
1.64 markus 2218: packet_disconnect("IP Spoofing check bytes do not match.");
2219:
2220: debug("Encryption type: %.200s", cipher_name(cipher_type));
2221:
2222: /* Get the encrypted integer. */
1.431 tedu 2223: if ((real_key_int = BN_new()) == NULL)
1.218 markus 2224: fatal("do_ssh1_kex: BN_new failed");
1.431 tedu 2225: packet_get_bignum(real_key_int);
1.64 markus 2226:
2227: protocol_flags = packet_get_int();
2228: packet_set_protocol_flags(protocol_flags);
1.220 markus 2229: packet_check_eom();
1.64 markus 2230:
1.431 tedu 2231: /* Setup a fake key in case RSA decryption fails */
2232: if ((fake_key_int = BN_new()) == NULL)
2233: fatal("do_ssh1_kex: BN_new failed");
2234: fake_key_len = BN_num_bytes(real_key_int);
2235: if (fake_key_len > sizeof(fake_key_bytes))
2236: fake_key_len = sizeof(fake_key_bytes);
2237: arc4random_buf(fake_key_bytes, fake_key_len);
2238: if (BN_bin2bn(fake_key_bytes, fake_key_len, fake_key_int) == NULL)
2239: fatal("do_ssh1_kex: BN_bin2bn failed");
2240:
2241: /* Decrypt real_key_int using host/server keys */
2242: rsafail = PRIVSEP(ssh1_session_key(real_key_int));
2243: /* If decryption failed, use the fake key. Else, the real key. */
2244: if (rsafail)
2245: session_key_int = fake_key_int;
2246: else
2247: session_key_int = real_key_int;
1.231 provos 2248:
1.66 markus 2249: /*
2250: * Extract session key from the decrypted integer. The key is in the
2251: * least significant 256 bits of the integer; the first byte of the
2252: * key is in the highest bits.
2253: */
1.431 tedu 2254: (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8);
2255: len = BN_num_bytes(session_key_int);
2256: if (len < 0 || (u_int)len > sizeof(session_key)) {
2257: error("do_ssh1_kex: bad session key len from %s: "
2258: "session_key_int %d > sizeof(session_key) %lu",
2259: get_remote_ipaddr(), len, (u_long)sizeof(session_key));
2260: rsafail++;
2261: } else {
2262: explicit_bzero(session_key, sizeof(session_key));
2263: BN_bn2bin(session_key_int,
2264: session_key + sizeof(session_key) - len);
2265:
2266: derive_ssh1_session_id(
2267: sensitive_data.ssh1_host_key->rsa->n,
2268: sensitive_data.server_key->rsa->n,
2269: cookie, session_id);
2270: /*
2271: * Xor the first 16 bytes of the session key with the
2272: * session id.
2273: */
1.170 markus 2274: for (i = 0; i < 16; i++)
1.431 tedu 2275: session_key[i] ^= session_id[i];
1.159 markus 2276: }
1.431 tedu 2277:
1.231 provos 2278: /* Destroy the private and public keys. No longer. */
1.169 markus 2279: destroy_sensitive_data();
2280:
1.231 provos 2281: if (use_privsep)
2282: mm_ssh1_session_id(session_id);
2283:
1.77 markus 2284: /* Destroy the decrypted integer. It is no longer needed. */
1.431 tedu 2285: BN_clear_free(real_key_int);
2286: BN_clear_free(fake_key_int);
1.64 markus 2287:
2288: /* Set the session key. From this on all communications will be encrypted. */
2289: packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
2290:
2291: /* Destroy our copy of the session key. It is no longer needed. */
1.418 djm 2292: explicit_bzero(session_key, sizeof(session_key));
1.64 markus 2293:
2294: debug("Received session key; encryption turned on.");
2295:
1.243 deraadt 2296: /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1.64 markus 2297: packet_start(SSH_SMSG_SUCCESS);
2298: packet_send();
2299: packet_write_wait();
1.98 markus 2300: }
1.426 markus 2301: #endif
1.98 markus 2302:
1.435 markus 2303: int
2304: sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen,
2305: u_char *data, size_t dlen, u_int flag)
1.404 markus 2306: {
1.432 djm 2307: int r;
1.435 markus 2308: u_int xxx_slen, xxx_dlen = dlen;
1.432 djm 2309:
1.404 markus 2310: if (privkey) {
1.435 markus 2311: if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen) < 0))
1.404 markus 2312: fatal("%s: key_sign failed", __func__);
1.435 markus 2313: if (slen)
2314: *slen = xxx_slen;
1.404 markus 2315: } else if (use_privsep) {
1.435 markus 2316: if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen) < 0)
1.404 markus 2317: fatal("%s: pubkey_sign failed", __func__);
1.435 markus 2318: if (slen)
2319: *slen = xxx_slen;
1.404 markus 2320: } else {
1.435 markus 2321: if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen,
1.432 djm 2322: data, dlen, datafellows)) != 0)
2323: fatal("%s: ssh_agent_sign failed: %s",
2324: __func__, ssh_err(r));
1.404 markus 2325: }
1.435 markus 2326: return 0;
1.404 markus 2327: }
2328:
1.98 markus 2329: /*
2330: * SSH2 key exchange: diffie-hellman-group1-sha1
2331: */
1.200 itojun 2332: static void
1.142 markus 2333: do_ssh2_kex(void)
1.98 markus 2334: {
1.422 markus 2335: char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
1.435 markus 2336: struct kex *kex;
1.437 markus 2337: int r;
1.102 markus 2338:
2339: if (options.ciphers != NULL) {
1.105 markus 2340: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1.102 markus 2341: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1.166 markus 2342: }
1.184 stevesk 2343: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
2344: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
2345: myproposal[PROPOSAL_ENC_ALGS_STOC] =
2346: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
2347:
1.166 markus 2348: if (options.macs != NULL) {
2349: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2350: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1.246 markus 2351: }
1.312 markus 2352: if (options.compression == COMP_NONE) {
1.246 markus 2353: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2354: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.312 markus 2355: } else if (options.compression == COMP_DELAYED) {
2356: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2357: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
1.102 markus 2358: }
1.380 djm 2359: if (options.kex_algorithms != NULL)
2360: myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms;
1.424 djm 2361:
2362: myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
2363: myproposal[PROPOSAL_KEX_ALGS]);
1.400 dtucker 2364:
2365: if (options.rekey_limit || options.rekey_interval)
2366: packet_set_rekey_limits((u_int32_t)options.rekey_limit,
2367: (time_t)options.rekey_interval);
1.327 deraadt 2368:
1.413 djm 2369: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
2370: list_hostkey_types());
1.134 markus 2371:
1.189 markus 2372: /* start key exchange */
1.437 markus 2373: if ((r = kex_setup(active_state, myproposal)) != 0)
2374: fatal("kex_setup: %s", ssh_err(r));
1.435 markus 2375: kex = active_state->kex;
1.426 markus 2376: #ifdef WITH_OPENSSL
1.263 markus 2377: kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1.292 djm 2378: kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1.263 markus 2379: kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1.324 djm 2380: kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1.378 djm 2381: kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
1.426 markus 2382: #endif
1.410 markus 2383: kex->kex[KEX_C25519_SHA256] = kexc25519_server;
1.186 markus 2384: kex->server = 1;
2385: kex->client_version_string=client_version_string;
2386: kex->server_version_string=server_version_string;
1.373 djm 2387: kex->load_host_public_key=&get_hostkey_public_by_type;
2388: kex->load_host_private_key=&get_hostkey_private_by_type;
1.231 provos 2389: kex->host_key_index=&get_hostkey_index;
1.404 markus 2390: kex->sign = sshd_hostkey_sign;
1.189 markus 2391:
1.435 markus 2392: dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
1.187 markus 2393:
2394: session_id2 = kex->session_id;
2395: session_id2_len = kex->session_id_len;
1.129 provos 2396:
2397: #ifdef DEBUG_KEXDH
2398: /* send 1st encrypted/maced/compressed message */
2399: packet_start(SSH2_MSG_IGNORE);
2400: packet_put_cstring("markus");
2401: packet_send();
2402: packet_write_wait();
2403: #endif
1.186 markus 2404: debug("KEX done");
1.278 markus 2405: }
2406:
2407: /* server specific fatal cleanup */
2408: void
2409: cleanup_exit(int i)
2410: {
1.386 djm 2411: if (the_authctxt) {
1.278 markus 2412: do_cleanup(the_authctxt);
1.423 djm 2413: if (use_privsep && privsep_is_preauth &&
2414: pmonitor != NULL && pmonitor->m_pid > 1) {
1.386 djm 2415: debug("Killing privsep child %d", pmonitor->m_pid);
2416: if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
1.388 djm 2417: errno != ESRCH)
1.386 djm 2418: error("%s: kill(%d): %s", __func__,
2419: pmonitor->m_pid, strerror(errno));
2420: }
2421: }
1.278 markus 2422: _exit(i);
1.1 deraadt 2423: }
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